Documentation/hwmon/it87 - kernel/msm-4.19 - Gitiles

 Kernel driver it87
 ==================

 Supported chips:
   * IT8705F
     Prefix: 'it87'
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/
   * IT8712F
     Prefix: 'it8712'
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/
   * IT8716F/IT8726F
     Prefix: 'it8716'
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/product_info/file/pc/IT8716F_V0.3.ZIP
                http://www.ite.com.tw/product_info/file/pc/IT8726F_V0.3.pdf
   * IT8718F
     Prefix: 'it8718'
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: Publicly available at the ITE website
                http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip
                http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip
   * SiS950   [clone of IT8705F]
     Prefix: 'it87'
     Addresses scanned: from Super I/O config space (8 I/O ports)
     Datasheet: No longer be available

 Authors:
     Christophe Gauthron
     Jean Delvare <khali@linux-fr.org>


 Module Parameters
 -----------------

 * update_vbat: int

   0 if vbat should report power on value, 1 if vbat should be updated after
   each read. Default is 0. On some boards the battery voltage is provided
   by either the battery or the onboard power supply. Only the first reading
   at power on will be the actual battery voltage (which the chip does
   automatically). On other boards the battery voltage is always fed to
   the chip so can be read at any time. Excessive reading may decrease
   battery life but no information is given in the datasheet.

 * fix_pwm_polarity int

   Force PWM polarity to active high (DANGEROUS). Some chips are
   misconfigured by BIOS - PWM values would be inverted. This option tries
   to fix this. Please contact your BIOS manufacturer and ask him for fix.


 Hardware Interfaces
 -------------------

 All the chips suported by this driver are LPC Super-I/O chips, accessed
 through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
 SMBus interface to the hardware monitoring functions. This driver no
 longer supports this interface though, as it is slower and less reliable
 than the ISA access, and was only available on a small number of
 motherboard models.


 Description
 -----------

 This driver implements support for the IT8705F, IT8712F, IT8716F,
 IT8718F, IT8726F and SiS950 chips.

 These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
 joysticks and other miscellaneous stuff. For hardware monitoring, they
 include an 'environment controller' with 3 temperature sensors, 3 fan
 rotation speed sensors, 8 voltage sensors, and associated alarms.

 The IT8712F and IT8716F additionally feature VID inputs, used to report
 the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
 the IT8716F and late IT8712F have 6. They are shared with other functions
 though, so the functionality may not be available on a given system.
 The driver dumbly assume it is there.

 The IT8718F also features VID inputs (up to 8 pins) but the value is
 stored in the Super-I/O configuration space. Due to technical limitations,
 this value can currently only be read once at initialization time, so
 the driver won't notice and report changes in the VID value. The two
 upper VID bits share their pins with voltage inputs (in5 and in6) so you
 can't have both on a given board.

 The IT8716F, IT8718F and later IT8712F revisions have support for
 2 additional fans. They are supported by the driver for the IT8716F and
 IT8718F but not for the IT8712F

 The IT8716F and IT8718F, and late IT8712F and IT8705F also have optional
 16-bit tachometer counters for fans 1 to 3. This is better (no more fan
 clock divider mess) but not compatible with the older chips and
 revisions. For now, the driver only uses the 16-bit mode on the
 IT8716F and IT8718F.

 The IT8726F is just bit enhanced IT8716F with additional hardware
 for AMD power sequencing. Therefore the chip will appear as IT8716F
 to userspace applications.

 Temperatures are measured in degrees Celsius. An alarm is triggered once
 when the Overtemperature Shutdown limit is crossed.

 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
 triggered if the rotation speed has dropped below a programmable limit. When
 16-bit tachometer counters aren't used, fan readings can be divided by
 a programmable divider (1, 2, 4 or 8) to give the readings more range or
 accuracy. With a divider of 2, the lowest representable value is around
 2600 RPM. Not all RPM values can accurately be represented, so some rounding
 is done.

 Voltage sensors (also known as IN sensors) report their values in volts. An
 alarm is triggered if the voltage has crossed a programmable minimum or
 maximum limit. Note that minimum in this case always means 'closest to
 zero'; this is important for negative voltage measurements. All voltage
 inputs can measure voltages between 0 and 4.08 volts, with a resolution of
 0.016 volt. The battery voltage in8 does not have limit registers.

 The VID lines (IT8712F/IT8716F/IT8718F) encode the core voltage value:
 the voltage level your processor should work with. This is hardcoded by
 the mainboard and/or processor itself. It is a value in volts.

 If an alarm triggers, it will remain triggered until the hardware register
 is read at least once. This means that the cause for the alarm may already
 have disappeared! Note that in the current implementation, all hardware
 registers are read whenever any data is read (unless it is less than 1.5
 seconds since the last update). This means that you can easily miss
 once-only alarms.

 The IT87xx only updates its values each 1.5 seconds; reading it more often
 will do no harm, but will return 'old' values.

 To change sensor N to a thermistor, 'echo 2 > tempN_type' where N is 1, 2,
 or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
 Give 0 for unused sensor. Any other value is invalid. To configure this at
 startup, consult lm_sensors's /etc/sensors.conf. (2 = thermistor;
 3 = thermal diode)


 Fan speed control
 -----------------

 The fan speed control features are limited to manual PWM mode. Automatic
 "Smart Guardian" mode control handling is not implemented. However
 if you want to go for "manual mode" just write 1 to pwmN_enable.

 If you are only able to control the fan speed with very small PWM values,
 try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
 it may give you a somewhat greater control range. The same frequency is
 used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
 read-only.
	Kernel driver it87
	==================

	Supported chips:
	* IT8705F
	Prefix: 'it87'
	Addresses scanned: from Super I/O config space (8 I/O ports)
	Datasheet: Publicly available at the ITE website
	http://www.ite.com.tw/
	* IT8712F
	Prefix: 'it8712'
	Addresses scanned: from Super I/O config space (8 I/O ports)
	Datasheet: Publicly available at the ITE website
	http://www.ite.com.tw/
	* IT8716F/IT8726F
	Prefix: 'it8716'
	Addresses scanned: from Super I/O config space (8 I/O ports)
	Datasheet: Publicly available at the ITE website
	http://www.ite.com.tw/product_info/file/pc/IT8716F_V0.3.ZIP
	http://www.ite.com.tw/product_info/file/pc/IT8726F_V0.3.pdf
	* IT8718F
	Prefix: 'it8718'
	Addresses scanned: from Super I/O config space (8 I/O ports)
	Datasheet: Publicly available at the ITE website
	http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip
	http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip
	* SiS950 [clone of IT8705F]
	Prefix: 'it87'
	Addresses scanned: from Super I/O config space (8 I/O ports)
	Datasheet: No longer be available

	Authors:
	Christophe Gauthron
	Jean Delvare <khali@linux-fr.org>


	Module Parameters
	-----------------

	* update_vbat: int

	0 if vbat should report power on value, 1 if vbat should be updated after
	each read. Default is 0. On some boards the battery voltage is provided
	by either the battery or the onboard power supply. Only the first reading
	at power on will be the actual battery voltage (which the chip does
	automatically). On other boards the battery voltage is always fed to
	the chip so can be read at any time. Excessive reading may decrease
	battery life but no information is given in the datasheet.

	* fix_pwm_polarity int

	Force PWM polarity to active high (DANGEROUS). Some chips are
	misconfigured by BIOS - PWM values would be inverted. This option tries
	to fix this. Please contact your BIOS manufacturer and ask him for fix.


	Hardware Interfaces
	-------------------

	All the chips suported by this driver are LPC Super-I/O chips, accessed
	through the LPC bus (ISA-like I/O ports). The IT8712F additionally has an
	SMBus interface to the hardware monitoring functions. This driver no
	longer supports this interface though, as it is slower and less reliable
	than the ISA access, and was only available on a small number of
	motherboard models.


	Description
	-----------

	This driver implements support for the IT8705F, IT8712F, IT8716F,
	IT8718F, IT8726F and SiS950 chips.

	These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
	joysticks and other miscellaneous stuff. For hardware monitoring, they
	include an 'environment controller' with 3 temperature sensors, 3 fan
	rotation speed sensors, 8 voltage sensors, and associated alarms.

	The IT8712F and IT8716F additionally feature VID inputs, used to report
	the Vcore voltage of the processor. The early IT8712F have 5 VID pins,
	the IT8716F and late IT8712F have 6. They are shared with other functions
	though, so the functionality may not be available on a given system.
	The driver dumbly assume it is there.

	The IT8718F also features VID inputs (up to 8 pins) but the value is
	stored in the Super-I/O configuration space. Due to technical limitations,
	this value can currently only be read once at initialization time, so
	the driver won't notice and report changes in the VID value. The two
	upper VID bits share their pins with voltage inputs (in5 and in6) so you
	can't have both on a given board.

	The IT8716F, IT8718F and later IT8712F revisions have support for
	2 additional fans. They are supported by the driver for the IT8716F and
	IT8718F but not for the IT8712F

	The IT8716F and IT8718F, and late IT8712F and IT8705F also have optional
	16-bit tachometer counters for fans 1 to 3. This is better (no more fan
	clock divider mess) but not compatible with the older chips and
	revisions. For now, the driver only uses the 16-bit mode on the
	IT8716F and IT8718F.

	The IT8726F is just bit enhanced IT8716F with additional hardware
	for AMD power sequencing. Therefore the chip will appear as IT8716F
	to userspace applications.

	Temperatures are measured in degrees Celsius. An alarm is triggered once
	when the Overtemperature Shutdown limit is crossed.

	Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
	triggered if the rotation speed has dropped below a programmable limit. When
	16-bit tachometer counters aren't used, fan readings can be divided by
	a programmable divider (1, 2, 4 or 8) to give the readings more range or
	accuracy. With a divider of 2, the lowest representable value is around
	2600 RPM. Not all RPM values can accurately be represented, so some rounding
	is done.

	Voltage sensors (also known as IN sensors) report their values in volts. An
	alarm is triggered if the voltage has crossed a programmable minimum or
	maximum limit. Note that minimum in this case always means 'closest to
	zero'; this is important for negative voltage measurements. All voltage
	inputs can measure voltages between 0 and 4.08 volts, with a resolution of
	0.016 volt. The battery voltage in8 does not have limit registers.

	The VID lines (IT8712F/IT8716F/IT8718F) encode the core voltage value:
	the voltage level your processor should work with. This is hardcoded by
	the mainboard and/or processor itself. It is a value in volts.

	If an alarm triggers, it will remain triggered until the hardware register
	is read at least once. This means that the cause for the alarm may already
	have disappeared! Note that in the current implementation, all hardware
	registers are read whenever any data is read (unless it is less than 1.5
	seconds since the last update). This means that you can easily miss
	once-only alarms.

	The IT87xx only updates its values each 1.5 seconds; reading it more often
	will do no harm, but will return 'old' values.

	To change sensor N to a thermistor, 'echo 2 > tempN_type' where N is 1, 2,
	or 3. To change sensor N to a thermal diode, 'echo 3 > tempN_type'.
	Give 0 for unused sensor. Any other value is invalid. To configure this at
	startup, consult lm_sensors's /etc/sensors.conf. (2 = thermistor;
	3 = thermal diode)


	Fan speed control
	-----------------

	The fan speed control features are limited to manual PWM mode. Automatic
	"Smart Guardian" mode control handling is not implemented. However
	if you want to go for "manual mode" just write 1 to pwmN_enable.

	If you are only able to control the fan speed with very small PWM values,
	try lowering the PWM base frequency (pwm1_freq). Depending on the fan,
	it may give you a somewhat greater control range. The same frequency is
	used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are
	read-only.